This invention describes a coupling assembly device used in the assembling of furniture, for joining or connecting two furniture elements, such as a side panel to a shelf, etc. This device enables the simple and fast assembly for furniture having parts made from wood to include wood panel, chipboard or particleboard, and medium density fiber (xe2x80x9cMDFxe2x80x9d) board. The invention is equally suitable for use with polyurethane foam or any flat furniture board pieces.
There are well known types of devices and/or procedures currently available for assembling furniture, both in the conventional fabrication of furniture as well as furniture sold in kits to be assembled by the customer, often referred to as xe2x80x9cready to assemblexe2x80x9d furniture. One well-known method for attaching furniture is to simply use bolts to attach the furniture pieces together. This procedure is not preferred in areas where the furniture is visible to the customer. Another method for attaching furniture pieces is to attach metallic wedges screwed into one element or component, attach either a hook or peg to the other member, and to attach the two pieces by attaching the hook or peg onto the metallic wedge. Although this process is efficient, having to incorporate metallic pieces is expensive both in material costs and in additional labor costs.
Cylindrical peg or other wedges, made of wood or any other material, are also used to attach furniture panels. The peg is inserted into the different components of the furniture and secured therein using an adhesive. The peg or wedge is then inserted into a mating hole or receptacle within the second furniture piece. Although this procedure is relatively simple, the disadvantage is that the furniture cannot be handled until the adhesive glue is dry. A more sophisticated version of this method is provided in U.S. Pat. No. 4,893,958 to Wieland, in which a rod attached to one component of the furniture is inserted within a hole in the second furniture complement. Set screws are used to secure the rod within the second piece of furniture.
Another prior art device for joining furniture is disclosed in U.S. Pat. No. 4,163,618 to Giovannetti. There, a finned shank having an adjustable headpiece is inserted with a slot within the first wood panel. The adjustable headpiece is configured so as to receive a head on a metal pin, which is attached to the second wood panel. A locking coin is also provided to secure the head of the metal pin within the adjustable headpiece of the first wood panel. Although this method is relatively simple to use, it requires having three different components each adding cost to the overall assembly process. Further, the assembly time is significant.
This invention address the drawbacks found in the prior art by providing a relatively inexpensive single unit coupling device that may be assemble quickly and efficiently, thereby reducing both material and labor costs
The present invention discloses a one-piece coupling device, preferably of a molded plastic or elastomeric material. The coupling device comprises a head portion and a bottom stem portion. In the preferred embodiment of the invention, the head portion comprises a front surface or front facing plate, a back body, and a top surface. The front facing plate is smooth and molded in the shape of a truncated pyramid. The back body surface extends outwards from behind the front facing plate and has a stepped or grooved appearance. The top surface of the back body is flat and has a centrally located cavity to accommodate a number of positioning tools. The bottom stem portion extends downwards from the base of the back body and is substantially cylindrical. The bottom stem has annular saw-tooth fins on its surface.
In operation, when joining a first wood panel to a second wood panel, the stem portion of the instant coupling device is inserted within a hole drilled in the first wood panel. The operator or assembler next inserts a positioning tool, for example a screwdriver or Allen wrench, into the cavity on the top surface of the head portion, in order to align the coupling device for attachment to the second panel. The second panel, having drilled therein a pyramid shaped mortise corresponding to the shape of the top portion of the coupling device, is manually clamped onto the head portion of the coupling device. The saw-tooth fins on the surface of the stem portion provides for secure attachment to the first wood panel, even without the need for an adhesive, although an adhesive may be used. The truncated pyramid shape of the head portion ensures that, once inserted, the second wood panel is prevented from moving in the lateral or traverse plane and can only move vertically on or off the head portion. However, this vertical movement is restricted by virtue to the interference fit provided by the grooves around the back surface of the head portion. The smooth front surface is sized so as to be slightly larger than the mortise drilled into the second wood panel. Thus, the front portion serves as a stop to limit the distance the head portion is inserted within the mortise. Also, the oversized front surface completely covers the mortise, thereby improving the appearance of the joint.
Hence, the instant invention provides numerous advantages over the prior art. First, the furniture coupling device is inexpensive to produce. The coupling device is made from an elastomeric material, preferably via an injection molding process. Next, the instant coupling device reduces the actual furniture costs by reducing the number of pieces needed to assemble the furniture. The instant furniture coupling device employs a one-piece connector that can be used on wood, particleboard, chipboard and MDF panels, making it extremely versatile. Further, the instant coupling device is easy to use, either manually or in a mechanized assembly process, thus reducing assembly time and costs, and lowering the level of expertise needed to assemble the furniture. Also, the instant coupling device may be dyed almost any color to match the furniture wood panels to be joined. This makes the instant invention more aesthetically pleasing than its prior art counterparts.